Process of purifying hydrocarbons



May 20, 1930.

J. c. BLACK-ET AL PROCESSl 0F PURI'FYIN-G HYDROCARBONS Fiied June fr, 1927 www 01 V NToRg fm2 w WNY NNM

Patented May 20, 1930 i UNITED siATEs' JOHN c. Binck, or Los ANGELES, AND'JOHN n. MccoivNELr., or WHITTIEB., CALI.4

PATENT *o1-rica FOBNILASSIGNOBS, BY MESNEASSIGNMENTS, T RICHFIELD-OIL COMPANY 0F CALIFORNIA, OF LOS ANGELES, CALIFORNIA, A CORPORATION O F- DELAWARE l'PROCESS' OF PRIFYING HYDROCARBONS This invention relates to the purification of hydrocarbons, and while not necessary thereto, it more specically refers to the ltreatment ofv na tha or gasoline synthetically produced by't e cracking of hydrocarbon oils,

Such as etr'oleum or shale oil, or distillates derived om la relatively high sulphur bearing crude oil in which free sulphur, hydrogen sulfide, or mercaptans may be formed during said distillation or cracking operation, are present in the final distillate.

" One of the principal objects of this invention is to accomplish a desulphurizing and purification of gasoline stock by a sequence"- of operations, to accomplish this purification rapidly and economically.- Another object of this invention is to provide a continuous process orbatch system 'for theextractionof free sulphur, hydrogen sulfide and mercaptans from gasoline stocks containing the same, b the employment of a metal dioxide in an a kaline aqueous suspension, commingling said --alkaline aqueous suspension of metallic dioxide with the gasoline stock under treatment, whereby free sulphur, hydrogen sulfide and mercaptans are oxidized with the formation of compounds having higher boilingpoints which may be thereafter separated by a ractionaldistillation process.

Another object of the invention is to produce a stable sweet gasoline stock by treat'- ing a sour gasoline with an excess of manganese 'dioxide-aqueous alkaline suspension to convert the sulphurcompoun'ds contained in the gasoline which has the properties of producing a fsour. reaction to compounds' that do not give this reaction, f' thus resulting in a sweet gasoline. Furthermore, certain sulphur compounds are converted to compounds of higher boiling point. which on subsequent distillation are removed by virtue of the increase in boiling point. Thetype'of chemical reaction in its simplest formwhich may take place in the above step is as follows:

With the fcregoingpr'elminary explainscarried out.

Application led June 7,1927. Serial No.` 197,150.

tion, the preferred embodiment. of our in' ventionwill now be more fully explained by reference to the accompanying drawing, which is a diagrammatical representation of an apparatus in which the invention is to be In the drawing 1 indicates generall a gasoline supply tank .containing the stoc to be treated, which is cbnnected lby a pipe 2 e near the bottom and leads to the suction side of a pump 4 controlled by a valve 3. Bump 4 4 discharges through the pipe 5, into the exchanger 6. A pipe 7 connects exchanger. 6 with a pipe 8. The said pipe 8 is connected to heater 9. Heater 9 is connected to a steam pipe 43 which leads to a source of steam not shown. 44 is a pipe connecting to said heater 9 and leads to a source of waste steam not shown. Pipe 10 connects the heater 9 to a reactionchamber 11. The reaction chamber 11 is provided with three outlet pipes 12, 14 and 16 controlled by the three valves 13, 15 yand 17, which are connected to the pipe 18. The pipe 18 is connected to the suction side of a pum 19, which discharges into a pipe 20 whic is connected to `branch pipes 22 and 24, controlled by the valves 21 and 23. The branch pipe 22 lis connected to exchanger 6.

'Exchanger 6 is connected to a cooler 45 by the pipe 25. The said cooler is provided with water inlet and outlet pipes 41 and 42. Th'e pipe 26 connects the cooler 45 to separator 27. A 4pipe 30 connects the separator i 27 at the bottom to a tank 32 controlled. by valve 31. A pipe 33 connects tank 32.at the bottom, controlled by a valve 34, and leads to a recovery plant not shown. A pipe 28- connects the separator 27 at the top to treated oil tank 29". A pipe 40 is connected to the treated oil tank 29 at the bottom controlled by a valve 39 and leads to a storage not shown.

46 is mixer provided with a caustic inlet pipe 37 and an 'air inlet pipe 38. This mixer 46 is provided with steam coils 50 which lead to a source of steam not shown. AA pipe 36,

controlled by valve" 35 connects a mixer 46 .on the suction side of pump 47. Pump 47 n'ected to the said heater 9.

The preferred process-as carried out discharges into' the pipe 8 which is conlthe apparatus just described, is as follows:

Gasoline or naptha stock to be treated, contained inthe tank 1, is discharged by the pump 4 through a heat exchanger 6, passing through pipes 5 and. The untreated oil passingthrough the heat exchanger 6 enters into a, heat exchange With the treated oil coming from the reaction chamber 11 where Y a temperature of approximately 100 to 150 F, is atta-ined. From heat exchanger 6 the v oiltofbe treated passes into a pipe 8 Where it meets a stream of Water solution of caustic alkali containing suspended manganese dioxide heated to a temperature of approximatelyv200 to 220 AF., and is commingled therewith and further heated to the reaction temperature which may vary from 200 to as high as 350 FL under a pressure sufficient to preventany substantial vaporization of rthe hydrocarbons or aqueous alkali solution,

during the passage through the heater 9. The commingled'oil and Water solution of caustic soda containing the suspended manganese dioxide heated to the reaction temperature, 200 to 350 F. pass under pressure suicient to prevent vaporization from the heater 9 into a reaction chamber 1l, where said products are maintained in a commingled state by a circulating agitation.

The circulating agitation in reaction chamber 11 is produced by taking suction through the pipes 12, 14 and 16 by pump 19 and discharging through the pipe 20 back into reaction chamber through the pipe 24, valve 21 being closed and valves 13, 15, y17 and 23 being open. 'As soon as the reaction is com' plete, the contents in the reaction chamber 11 are discharged to a separator27, passing through pipes 22, exchanger 6 and .coolerm45. In somelcases, it may be desired to operate continuously, in which case a circulating agitation is maintained in thereaction chamber 24 and at the same time the oil containing'the commingled agents is continuously discharged into the said separator'tank 27.l

The oil containing the commingled agents pass through exchanger 6 in counteriowheat is drawn oil" into the tank 32 passing through a pipe 30 controlled by the valve 31, and the purified oil passesv out the top ofthe ,sepa-- rator, passing through the pipe 28` and into thetreated'oil tank 29. Y 'y The swcetening mediumemployed for this purification las heretofore statedcomp'r'ises a mixture of manganese dioxide suspended in' an aqueous solution of a caustic alkali; preferably a solutlon of caustic soda 1s used ranging from 15 Baume to as high as 25 Baume l or higher, and commin-gling therewith from 1 to as high as 5 per centor more by Weight sour gasoline preferably a mild agitation either continuous or intermittent, is maintained and within 5 days the gasoline will have become sweet. vThis treatmentl is preferably carried out in storage tanks. v

The mixing of these agents is diagrammatically shown in the drawing, 46 being a mixer tank of any preferred type containing the steam heating coils 50. The caustic soda is introduced into the mixer through the pipe 37 and the manganese dioxide inthe required proportions is introduced into the mixer tank 46 through the man hole 51. The Water solution of caustic soda-containing the required percentage of manganese dioxide is commingled by an air agitation through the air inlet'pipe 38.- f The mixing of the Water solution'of caustic soda and manganese dioxide may be carried out continuously or intermittently as the case demands and is preferably heated to a temperature of approximately 200 t0 220 F;

The spent solution of caustic soda and man- A ganese dioxide contained in the tank 32 may `be partly recovered for re-use by methods well known in the art.

It is to be understood that any petroleum stock may be treated by this method for the removal' of any sulphur `bodies having the general formula RSI-I in which R may be hyydrogen or any organic radical.y

As a specific example, in the treatment of gasoline stocks derived from cracking California petroleum oil distillates, it wasfound that the amountl of caustic soda solution of 25 Baume containing 1 to 5 per cent by weiofht,

manganese dioxide ranging from 5 to as hlgh as 15 per cent by volume,.would remove satisfactorily the mercaptans, hydrogen sulfide and free sulphur from the same. It was fou-nd desirablein all cases to use a'considerable excess of the purifying vagents 'and there-,'

after recovering the agents by rnethodszwell known in the art. f

-By the 4term Fsour we means-,a petroleum oil containing-mercaptans, hydrogen sulde, or any 'other sulphur compound that reacts withtheI doctor solution, and bythe term ,Y I sweet we means` a petroleum oil substan-f vtially free of the above named-sulphur constituents. B y the term doctor test We mean that well-known test employed by chemists to determine a sour or sweet petroleum oil stock, the term negative to doctor test meaning that oil stock is sweet; positive to the doctor test meaning that the oil stock is soun It is also to be understood that any gasoline stock or petroleum oil distillate may be treated by our invention and rendered sweet, and that any petroleum oil distillate may or may not have had prior treatments known in the art, such as treatments with acid and caustic soda before being sweetened by our invention.

Preferably, this treatment is followed by a distillation with steam at a temperature approximately not exceeding 325 F. in order to obtain a finished water white gasoline stock which will retain a water white color and remain sweet to the doctor test. However, it is to be understood that this treatment may or may not be followed by a distillation operation, this depending upon the stock to be treated and the color desired. In case a colored gasoline is to be manufactured, a distillation operation may not be necessary.

By the term caustic alkali we mean either caustic soda or caustic potash.

While the process herein described is well adapted for carrying out the object ofthe present invention, it s understood that various modifications may be made without departing from the spirit of the invention and the invention includes all such modifications and changes as come within the scope of the appended claims.

We claim l l. A process of purifying liquid hydrocarbons comprisingv treating the same with an aqueous solution of caustic alkali containing suspended manganese dioxide at an elevated temperature and under suiiicient pressure to substantially prevent vaporization of the hydrocarbons and the aqueous solution of caustic alkali to render the hydrocarbons sweet to the doctor test, then separating the treatedhydrocarbons from the residual aqueous solutionof caustic alkaliy and manganese dioxide compounds and distilling the treated hydro carbons at a temperature not greater than the temperature employed inthe sweetening step.

2. A process of purifying liquid hydrocar- 'bons comprising treating the same with an aqueous solution of caustic alkali-containing suspended manganese dioxide at a temperature of approximately 325 F. to substantially immediately oxidize the sulphur bearing conature substantially not greater than 325 F.

In testimony whereof we aiix our signastituents and lto render the hydrocarbons M sweet to the doctor test, and separating the treated hydrocarbons from the residual 4aqueous solution of caustic alkali and manganese dioxide compounds, and distilling the treated hydrocarbons with steam at a temperssv 

